Automatic drilling machine



March 11, 1952 c. M. O'LEARY 2,589,121

, AUTOMATIC DRILLING MACHINE Filed June 15, 1946 a Sheets-Sheet 1 BY E-L- W9 V/ZM March 11, 1952 c. M. OLEARY 2,589,121

AUTOMATIC DRILLING MACHINE Filed June 15, 1946 3 Sheets-Sheet 2 [I] I Aw Q m IN V EN TOR.

March 11, 1952 c. M. O'LEARY 2,539,121

AUTOMATIC DRILLING MACHINE Filed June 13, 1946 r 3 Sheets-Sheet 3 I, If

' INVEN TOR.

Patented Mar. 11, 1952 UNITED STATES PATENT OFFICE .20 Claims.

The present invention relates to rotary well drilling machines and constitutes an improvement on the invention disclosed in applicant's copending applications, Serial No. 602,620, filed June 30, 1945 on Automatic Well Drilling Mechanism, and Serial No. 647,677, filed February 15, 1946.

Rotary well drilling machines conventionally include .a hoisting mechanism for hoisting, lowering or supporting part of the weight of the drill stem, a rotary table for rotating the drill stem, one or more slush pumps .for forcing the drilling fluid or mud into the drill stem during drilling, and a suitable source of power. The operation of drilling requires a simultaneous supply of power to the rotary table and slush pump while the weight of the drill stem is partially supported by a hand-operated brake band on the hoisting drum. As the drilling progresses.

additional lengths of drill stem are added from time to time. When it is necessary to change drill bits, all of the drill stem must be hoisted step by step and the successive lengths disconnected and laid aside. In order to reduce the time lost in removing the drill stem from the hole and reinserting the stem, the hoisting and lowering operations must be conducted at high speed. Since, particularly in deep drilling operations, the weight of .the drill stem is exceedingly high, this necessitates the application of great power to the hoist for rapid hoisting and exceedingly high braking forces to the drum in order to terminate each successive lowering Operation in the minimum time interval. During drilling operations, lesser amounts of power are required to separately drive the rotary table and theslush pumps.

In applicant's copending application, Serial No. 647,677, filed February 15, 19.46, means are provided for achieving the above results, including a plurality of engines which are connected through individual hydrokinetic torque converters and a multiple speed transmission either jointly to the hoisting drum or separately to the. slush pump and rotary table. The multiple speed transmission may be controlled manually or, in the case .of hoisting, may be subject to automatic control effective to maintain the speed ratio of the torque converters within an efficient range. "The torque converters may be employed to brake the hoisting drum during drill stem lowering operations. To make pos-, sible operation of the torque converters at inefficient speed ratios, including stall and reverse braking conditions, they are preferably provided with differentially driven cooling mechanisms of the type disclosed in applicant's copending applications, .Serial No. 571,656, filed January '6, 1945, and now abandoned and Serial No. 666. 26. flledMay 2,. 1946.

.It has "been proposed that for drilling purposes. means be provided for varying the pressure of the drill bit on the bottom of the hole inversely with respect to the torque required to drive the rotary table in order to obtain optimum drilling conditions and avoid twist-oils of the drill stem. In applicants copending application, Serial No. 602,620, filed June 30, 1945, improved means for this purpose are disclosed. The mechanism there disclosed is characterized by the fact that an increase in the table torque imposes an increased lifting force on the hoisting drum which is a lower percentage of the total lifting force exerted by the drum on the drill stem than the percentage increase in table torque. This result is achieved automatically by transmitting to the hoisting drum a substantially constant drill stem lifting torque which is sufficient to balance the major portion of the weight of the drill stem and by driving the rotary table through a differential mechanism which imposes an additional drill stem lifting torque on the drum which is proportional to the table torque but which in no case exceeds a minor proportion of the force required to support the drill stem.

It is a general object of the present invention to provide an improved rotary drilling machine incorporating all of the features of the previous inventions in the copending applications in a compact, practical mechanism.

Another object of the present invention is to provide, in the drive connection between the engine and the hoisting drum and table, a single multiple speed ratio transmission mechanism of improved design and construction which may be selectively employed to change the speed ratio in the drive connections to either the hoisting drum or the table.

Another object is to provide a transmission mechanism of the type last mentioned which in-' cludes a change speed planetary transmission unit effective to vary the speed ratio in the drive from the engines to either the hoisting drum or the rotary table when they are driven separately, and which may also be employed during automatic drilling to impose on the hoisting drum a drill stem balancing force proportional to the table torque.

Another object of the present invention is to provide an improved and simplified means for varying the ratio between the table torque and the tabletorque reaction imposed upon the drumduring automatic drilling.

Another object of the present invention is to provide, in connection with thehoisting drum, a combination two-speed transmission and clutch unit which is positioned to a large extent within the confines of the usual brake flange on the hoisting drum.

Another object of the present invention is to provide an improved selective drive connection between a plurality of engines and the slush pump, rotary tableand hoisting drum of a'drillbination of engines may be operatlvely con- Figure 1 is a more or less diagrammatic planview showing the general arrangement of the major elements of the complete machine, with the slush pump and rotary table omitted;

Figure 2 is an enlarged plan view, partly in section, of the hoisting drum and transmission units disclosed in Figure 1;

Figure 3 is a fragmentary transverse section taken on the line 33 of Figure 2;

Figure 4 is a fragmentary section taken on the line 44 of Figure 2'; and

Figure 5 is an elevation view taken partly in section on the line 5-5 of Figure 2.

As best shown in Figure 1, the preferred form of the apparatus includes three engines I, 2 and 3, the output shafts of which are connected, respectively, to the input shafts 4, 5 and 6 of three hydrokinetic torque converters 1, 8 and 9. The output shafts In, H and I2 of the torque converters extend into a suitable housing, indicated generally at |3. Each of the hydrokinetic torque converters is provided with a fluid cooling unit including a differentially driven air circulating fan and indicated generally at |4, l5 and H5. Since the detailed design and construction of the engines, the torque converters and the differentially driven cooling units, per se, form no part of the present invention, they need not be further described. However, reference may be had to applicants copending applications, Serial No. 571,656, filed January 6, 1945,- and Serial No. 666,626, filed May 2, 1946, for a more complete disclosure of these features.

The output shaft IU of torque converter 1 projects entirely through the housing l3 and carries a multiple V-belt pulley H, which is freely journaled on the shaft H! but may be connected thereto by engagement of an air operated clutch, indicated diagrammatically at l8. A multiple V-beltdrive, indicated generally at l9, extends from the pulley H to the slush pumps, not shown, in the usual manner.

A sprocket 20 is fixed on the shaft l6 within the housing |3 and is connected by means of a chain 2| to a sprocket 22, which is freely journaled on the shaft within the housing but which may be connected to the shaft II by engagement of an air operated clutch, indicated generally at 23. A second sprocket 24 is fixed on the shaft within the housing I3 and is connected by a chain 25 to one of a pair of fixedly connected sprockets 26 and 21, which are freely journaled on the shaft |2 within the housing. The other sprocket 21 of the pair is connected by a chain 28 to a sprocket 29 fixed on a countershaft 38, which is journaled in any suitable manner on the base of the drilling machine, not shown. A sprocket 3| is fixed on the shaft |2 within the housing l3 and connected by a chain 32 to a sprocket 33, which is one of a pair of sprockets 33 and 34 which are fixedly connected together and freely rotatable upon the shaft 30. The double sprocket 33 and 34 may be fixed to the shaft 30 by engagement of an air operated clutch, indicated diagrammatically at 35.

As a result of the above connections, it will be apparent that engine 2 is always connected to shaft 30, that engine 3 may also be connected to shaft 30 by engaging clutch 35, or engine I may also be connected to shaft 30 by engaging clutch 23. All three of the engines may be connected to shaft 36 by engaging both of the clutches 23 and 35. It will also be noted that engine 3 is always connected to the double sprocket 33-34. Engine I may be connected to the slush pump by engaging clutch l8; engine 2 may be connected to the slush pump by engaging clutches I8 and 23; and all three of the engines may be connected to the slush pump by engaging clutches I8, 23 and 35.- Thus, a wide variety of combinations of engine drive connections may be achieved by the control of only three clutches.

The opposite end of the shaft 30 is provided with a sprocket 36, which is normally freely rotatable with respect to the shaft 38 but may be fixed thereto by operation of an air clutch 31. The sprocket 34 of the double sprocket 33-34 is connected by a chain 38 to a sprocket 39 mounted on a tubular shaft 40 projecting from one end of a multiple speed transmission, indicated generally at 4|, while the sprocket. 36 is connected by a chain 42 to a sprocket 43 ona,

shaft 44 projecting from the opposite end of the transmission 4|. Likewise fixed to the shaft 44 is a sprocket 45 which is connected by a chain 46 to the drive sprocket 41 for the hoisting drum, indicated generally at 48. The transmission 4| has a second output shaft 49 projecting from its right-hand end and connected by a pair of change gears 56 and 5| to a countershaft 52 upon the ends of which are mounted a pair of cat heads 53 and 54. A sprocket 55 is normally freely rotatable upon the countershaft 52, but may be .fixed thereto by engagement of an air operated clutch 56. Sprocket 55 is connected by means of a chain 51 to a double sprocket 5859 journaled on a shaft 60, and the sprocket 59 is connected by a chain 6| to a conventional rotary table (not shown). The shaft 52 is positioned at a substantially higher elevation than the axis of transmission 4| and, consequently, the chain drive 51 will pass over the right-hand support for theistationary drum shaft. In addition to the cat heads and sprocket 55, shaft 52 carries a sprocket 62 from which the usual sand reel may be driven by a suitable chain.

It will be apparent from the mechanism so far described that one or more of the engines may be connected through chain 38, tubular shaft 40.and transmission 4| either to the hoisting drum 48 or to the rotary table through shaft 49 and the table drive connections. Alternatively, by engaging clutch 31, a drive may be established directly to the hoisting drum from shaft 30 through chain 42, sprockets. 43 and 45 and chain 46, or shaft 38 may be connected to the table through chain 42, shaft 44, transmission 4|, shaft 49 and the associated table drive connections. In addition, as hereinafter more fully pointed out, the tubular shaft 46 maybe fixed to the shaft. 49 by engagement of a dog clutch 63. In that case, the chain drive 38 may drive into the transmission 4| through shaft 49 to drive the hoisting drum in reverse, or the chain drive 3 may drive the shaft 49 and,by engagement of clutch 56, the countershaft52, thus providing a direct drive for the table, the cat heads or the sand reel. v I, Q

As best shown in Figure 2, the transmission 4| includes a pair of planetary transmission units connected in series and indicated generally at 64 and 65. Transmission unit 64 includesthe previously mentioned tubular input shaft 40 and a V wise rotation of the cage.

tubular output shaft 65on which is fixed a pair of sun gears '61 and 68, respectively. The tubular shaft 49 is journaled by means of suitable bearings 69 on the casing 79 of the transmission, and both of thetubularshafts are journaled by means of suitable bearings on the internal shaft 49, which extends internally through the transmission 41 and is journaled at its ends in bearings "and 12. The gears 61 and 68 mesh with a plurality of planet gear clusters, one of which is indicated generally at 73. Each gear cluster is journaled in a planet cage M, which, in turn, is journaled upon the tubular shafts 40 and 65.

As the result of this construction and the relative sizes of the gears in the transmission unit 64, rotation of the tubular input shaft 40 will effect rotation of the tubular output shaft 65 in the same direction but at a reduced speed when the planet cage 14 is held stationary. Any desired-change in the speed ratio may be provided but, for purposes of illustration, it may be assumed that under the above stated conditions shaft 65 is rotated at one-half the speed of shaft 40. When torque is transmitted from shaft 49 to shaft 66 in this manner, a torque reaction on the planet cage 74 is in a direction opposite to that of the torque delivered to shaft 66.

With the particular connections illustrated in the drawings, shaft 40 will tend to rotate in a counterclockwise direction, as viewed in Figure 3, and, consequently, the torque reaction on the planet cage M will tend to cause a clockwise rotation of the cage. In order to prevent such rotation automatically and thus hold the planet cage stationary, a plurality of one-way clutch blocks is provided between the housing W and the planet cage. The construction of one of these clutch blocks is shown in section in Figure 3. As there illustrated, the casing 14 is provided with an opening 75 which is closed by means of a cover plate 16 having a cylinder Tl formed therein. A one-way clutch block it is fitted between the flat underside of the cover plate Hi and the periphery of the planet cage M in such a mannerthat any tendency of the planet cage to rotate in a clockwise direction will cause a wedging of the block 78 between the cover plate and the cage and thus act to prevent such rotation. A coil spring 19 normally urges the clutch block toward wedging position. It will be observed, however, that the clutch block 78 will not resist rotation of the planet cage in a counterclockwise direction. Means are provided for shifting the clutch block 18 to the left, as viewed in Figure 3, when it is desired to permit clock- This means includes a pair of pistons 80 and 8| positioned within the cylinder 7! and a piston rod 82. A dog 83 is fixed to the rod 82 and projects through a suitable slot in the plate 76 into a position opposite the end of clutch block 78. A coil spring 84 normally holds the pistons and associated dog 83 in an inoperative position, as illustrated in Figure 3, in which position the dog does not interfere with normal operation of the block 78. When it is desired to render the block 18 inoperative, air under pressure is admitted through a pipe 85 at the right-hand end of the cylinder ll, thus forcing the pistons and dog to the left and disengaging the block 78. Under these circumstances, the planet cage is free to rotate in clockwise direction, as viewed in Figure 3.

.Means are provided for establishing a 1-1 driving connection between the tubular shafts 48 and 66. This means includes a separate clutch cone 86 fixed axially on each planet gear :cluster and a plurality of cone clutch elements 81 carried by a plate 88, which is rotatably journaled on the tubular shaft 40. The inner portion of the plate is provided with an annular recess 89, which constitutes a cylinder adapted to receive an annular projection or stationary piston '90 fixed 1x) the casing Tit. When air is supplied through a pipe 9! to the interior of the cylinder 8%, the plate '88 will be shifted to the left. as viewed in Figure 2, thus engaging the planet cluster cone clutches and thereby preventing rotation of the planet clusters about their own axes. This establishes .a 1-1 drive connection between the tubular shafts 4E] and 66. Since on such rotation, the planet cage turns with the tubular shafts 4!] and .66 in a counterclockwise direction, as viewed in Figure 3, the one-way clutch blocks 19 automatically disengage. When no air is supplied through pipe 9|, the planet cluster cone clutches are disengaged bya plurality of coil springs positionedbetween the planet cage 74 and the plate 88 in the positions indicated .in dotted lines at 92 in Figure 3.

Thus, the planetary'transmission unit 64 automatically provides one speed ratio when air is admitted under pressure to pipe 9| and another when no pressure is applied through that pipe. Any suitable means under either manual :or automatic control maybe provided for supplying air to the pipe 9! as desired, a suitable apparatus for that purpose being disclosed in applicants c0- pending application, Serial No. 647,677, filed February 15, .1946.

Fixed to the tubular shaft 86 :is an enlarged brake flange 93, which is adapted to be engaged by a plurality of one-way clutch blocks similar in-construction and mode of operation to the previously described clutch blocks 18. However, the clutch blocks $4 associated with the flange 93 are positioned on the opposite side of the clutch block release dog 84a, as compared with the arrangement shown in Figure 3. Consequently, when air under pressure is supplied to the cylinder 94b, the clutch blocks 94 may engage and prevent counterclockwise rotation of the flange 93, as viewed from the right-hand 'end of the transmission. When no air is supplied to the cylinder 94b, springs similar to the spring 84 shift the clutch blocks 94 to inoperative position. Since the mechanism for holding the brake flange 93 and, consequently, the tubular shaft 66 stationary is otherwise identical to that illustrated in Figure 3, further illustration or description isv believed unnecessary.

Tubular shaft 65 is fixed in any suitable manner to the tubular input shaft '95 of the second planetary transmission 65. The shaft '95 is journaled in suitable bearings 96 carried by a web .91 forming a portion of the housing 70, and is also journaled by additional bearings on the internal shaft 49. The previously mentioned tubular output shaft M of the transmission 4i constitutes one output shaft of the transmission unit 65, the shaft 44 being journaled in suitable bearingsllB carried by the casing and also being journaledon the internal shaft 49. The tubular shafts 44 and carry spur gears 99 and H36, respectively, which mesh with .a plurality of planet gear clusters. Each .of these clusters includes two gears fixedly connected together, and one of the clusters is in dicated generally at Iiil in Figure 2. The planet which .is journaled on the shafts M and '95 and 7 p which is fixed by means of a central web I03 to the internal shaft 49 in any suitable manner.

It will be observed that the planet cluster gears of transmission unit 65 are reversed in their position with respect to those in transmission unit 64, with the result that when power is supplied to the shaft 95 and the planet cage I02 is held stationary, shaft 44 will rotate in the same direction as shaft 95 but at a higher speed. During such operation, the torque reaction on the planet cage I02 tends to rotate the planet cage in the same direction as the shafts 44 and 95, namely a counterclockwise direction, as viewed in Figure 4.

As best shown in Figure 4, means are provided for selectively preventing rotation of the planet cage I02 in either direction. This means comprises a plurality of pairs of oppositely disposed one-way clutch blocks I04 and I05, which are adapted to be wedged between the periphery of planet cage I02 and the undersurface of a plate I05 fixed to the casing 10. A cylinder I01 is fixed to the plate I06 and contains a pair of pistons I08 and I09 connected by a piston rod IIO to which is fixed a dog III. A spring II2 normally urges the pistons and associated dog I II to the right, as viewed in Figure 4, thereby effecting disengagement of the one-way clutch block I05. When air under pressure is admitted to pipe I I3, the pistons and associated dog III are shifted to the'left against the action of the spring II2, engage the one-way clutch block I 04, and render that clutch block inoperative. Normally no air isapplied to the cylinder I01, and consequently, the parts remain in the position shown in Figure 4, in which the planet cage I02 is free to rotate in a counterclockwise direction, as viewed in that figure.

In order to establish a 1-1 drive connection through the transmission unit 65, each of the planet gear clusters is provided with a clutch coneelement II4 adapted to cooperate with a cone clutch II5 carried by a plate IIB journaled on shaft 95. The construction and arrangement of the cone clutch elements H4 and associated clutches I I5 are identical to that of the previously described clutch cones 86 and associated clutches 81 except that the apex of the cone clutches is reversed. Consequently, when air is supplied through a pipe II1 to the annular clutch operating cylinder II8, the clutch plate II6 is shifted to the left, as viewed in Figure 2, thereby disengaging the cone clutches. A plurality of coil springs II9 positioned between planet cage I02 and the clutch plate H6, in the positions best indicated in Figure 4, normally operates to hold the cone clutches H5 in engagementiwith the clutch cones II4, thereby locking the planetary transmission unit 55 in a 1-1 ratio.

In order to provide additional speed ratios in the drive connections to the hoisting drum and at the same time secure a disengageable clutch connection between shaft 44 of transmission 4I and the hoisting drum, an additional two-speed planetary transmission, indicated generally at I20, is positioned within the brake drum flange I2I of the hoisting drum 48. Since this transmission is to a large extent identical in construction to the transmission unit 64 previously described, a detailed description of the mechanism is unnecessary. It may be noted, however, that the transmission is so arranged that when the planet cage I22 thereof is held stationary, the drum will be rotated at a lower speed than the drive sprocket 41. When the planet cage cone clutches I23 are engaged, the drum wilLrotate at the same speed as the drive sprocket 41. The cone clutches I23 are engaged by air pressure and disengaged by spring pressure, in the manner described in connection with the clutches 81. The air for effecting engagement of the clutches I23 is supplied through a pipe I24 to a passageway I21 in the stationary shaft I25 which supports the hoisting drum. The passageway I21 communicates with an annular space I28 surrounding the shaft I25 and defined by a pair of seals I29 and I30. The annular space I28, in turn, is connected by a passageway I3I to the interior of the cylinder I32 formed by the cone clutch plate.

While, if desired, one-way clutch blocks or the type shown in Figures 3 and 4 may be employed to hold the planet cage I22 stationary when desired, in the preferred form of the invention illustrated this function is performed by means of a brake band I33 which engages the periphery of the planet cage. As best shown in Figure 5, one end of the brake band isadjustably anchored by an eye-bolt I34 to an arm I35, which is fixed to the frame I36 that supports the shaft I25. The arm I 35 projects within the drum flange, as best shown in Figure 2, to serve as an anchor for the brake band I33. The opposite end of the brake band I33 is fixed eccentrically at I38 to a cylindrical member I39, which is journaled on the arm I35. The arm I40 fixed to the cylindrical member I39 is normally held in the position illustrated in Figure 5, in which the brake is applied, by means of a coil spring I4I positioned within a cylinder I42 and acting on a piston I43 which is connected to the arm I40 by a piston rod I44. When air under pressure is supplied through a pipe I45, the spring I4I will be compressed and the arm I40 rotated in a clockwise direction, as viewed in Figure 5, thereby releasing the brake.

It will be apparent from the above that when no air is supplied to either of the pipes I24 and I45, the transmission unit I20 will be in its lower speed ratio, in which the drum rotates at a speed less than that of the drive sprocket 41. Application of air under pressure to both of the lines I24 and I45 will establish the higher or 1-1 speed ratio drive between the sprocket 41 and the drum. If air is supplied only to the pipe I45, the sprocket will be disconnected from the drum and the latter will then be free of all drive connections to the transmission. The hoisting drum 48 is provided with a pair of brake bands I46 and I41 adapted on application to hold the drum stationary in the usual manner.

It will be apparent that in lieu of the clutch blocks employed in connection with the planetary transmission units 64 and 65 and the-brake flange 93, brake bands similar in construction and mode of operation to that illustrated in Figure 5 may be employed. However, the one-way clutch blocks are preferred inasmuch as they may be spaced equally about the periphery of the planetary cage or brake flange, with the result that the braking loads on the bearings of the transmission are balanced.

While the means for supplying air to effect engagement of the clutches I8, 23, 35 and 31 are not illustrated, they may be supplied with the air through the clutch shafts by passageways in the shafts communicating with stationary air supply manifolds mounted on the ends of the shafts in the usual manner. The air supply for the clutch 56 is similarly arranged except that the air supply manifold is preferably located intermediate the ends of the shaft 52. The interior constructionand mode of operation of these air clutches may be of any known or conventional type.

The number and magnitude. of the different speed ratios provided by the transmission mechanism of the present invention may be varied widely, as desired, by changing the relative sizes of the sprockets and gears employed in the .mechanism. However, for purposes of illustration, it will be assumed that the relative proportions of these elements are as follows. All of the sprockets 20, 22, 24, 26, 21, 29, 31, 33, 34 and 39 are of the same size. Transmission unit 64 is .so proportioned that when the planet cage I4 is held stationary, shaft 66 will rotate in the same direction but at half the speed of shaft 49.

Transmission unit 65 is of such construction that when the planet cage I32 is held stationary,

shaft 95 will rotate in the same direction and at "half the speed of shaft 44; when shaft 44 is held stationary, planet cage Hi2 will rotate in thesame direction but at twice the speed of shaft '95; and when shaft 95 is held stationary, planet cage I62 will rotate in the opposite direction from thatof shaft 44 but at the same speed.

The diameter of the sprocket. 43 is four times the may be varied at will by substituting different: sets of change speed gears 53 and 5|, but. may,

for example, be a ratio. of approximately 6-1 between the speed of shaft 49 and the speed of rotation of the table.

The operation of the transmission mechanism. is" as follows:

Hoisting When no control air is supplied to any of the clutches or brakes in the apparatus and the manually operated clutch 63 isv disengaged, en-,

gjne 3 is connected to the hoisting drum 48: and the overall transmission drive is in its lowest speed ratio, which, in the example given above,

would be a ratio of 12-1 between the speed of rotation of the. shaft I2 and the speed of rotation .of the drum 48. The drive to the drum under these conditions is from shaft I2 through sprockets 3|, 33, 34 and 3 9 to the. tubular input shaft 40 of the transmission 4|.

- Under these conditions, the clutch 81 will be .held disengaged by the springs 92 and the planet cage. M will be held against clockwise rotation,

,as. viewed in Figure 3, by the one-way clutch l'bl'ocks I8. Consequently, shaft I56- will rotate in the same direction as shaft 46 but at half. speed.

Since no air is supplied to the cylinder 9411, the clutch blocks 9% for the flange 93 will be held in inoperative position, thus permitting rotation of the shaft 66 and the connecting input shaft .95 of the transmission unit 65.

Since no air is supplied through the. pipe Ill to disengage clutch H5, that clutch. will be held engaged by Consequently. Shaft 44v will be with, the shafts 44 and 95, is free to rotate in its forward or clockwise direction, as viewed in Figure 4,, since the clutch. blocks I05. are. held in inoperative position. by the springs I.I2. A double sprocket 43-1-45 is fixedito. the shaft 44.

and, consequently, drives the sprocket 41 for the hoisting drum. The cage I22 of the drum planetary transmission unit I20 will be held stationary by the brake band I33, since no air is supplied to the pipe I45, and the clutches I23 will be held disengaged by their clutch release springs, which are similar in construction and operation to the previously mentioned springs 92. Therefore, the hoisting drum will rotate in the same direction but at one-half the speed of the sprocket 41. Since clutch 56 is disengaged, no power will be supplied to the rotary table under these conditions.

None of the. clutches I8, 23, 35 or 31 is involved in any of the speed ratio changes required during forward or hoisting rotation of the drum 48. Consequently, in the lowest speed ratio drive connection mentioned above or in any of the higher speed ratios hereinafter described, additional engines may be connected to the. drum through the transmission withoutv changing the mechanical speed ratio in the drive connection. Thus, if in addition to engine 3 it is desired to connect engine 2 to the drum, clutch 3.5 is engaged. If it is desired to connect all three of the engines to the drum, clutches 2-3 and 35 are engaged.

In order to establish the second or next higher speed ratio to the transmission, it is only necessary to supply air through pipe to efiect engagement of the cone clutches ii? of transmission unit 64. This provides a 1-1 direct drive through the transmission unit 6% and thus doubles the speed ratio of the overall drive. Under these conditions, the speed ratio between shaft I2 and the drum is 6-1. The next higher speed ratio is achieved. by simultaneously supplying air under pressure to the previously mentioned pipe SI and-also to the pipes H3 and Ill. The application of air pressure through the pipe I I1 disengages the cone clutch elements H5 and the application of air through the pipe I ll shifts the clutch block dogs III to the left, as viewed in Figure 4, thereby permitting the clutch blocks I05 to hold the planet cage I82 against counterclockwise rotation, as viewed in Figure 4. Under these circumstances, the planet cage remains stationary and shaft 4-5 is rotated in the same direction but at twice the speed of shaft 95. This increases the overall speed ratio between the shaft I2 and the drum to a ratio of 3-1.

To provide the fourth or highest speed ratio, air under pressure is supplied simultaneously to the pipes 9|, H3, II'F', I24 and I45. This involves no change of the conditions within the transmission 4| but effects a 1-1 drive connection through the planetary transmission unit I 23 between the drive sprocket 4! and the drum 48. This provides an. overall speed ratio between the shaft I2 and the drum of 1 -l.

It will be appreciated that the four different speed ratios thus provided may be obtained either by manually actuating suitable control valves in the air pressure supply lines or by subjecting such control valves to the action of an automatic shifting control mechanism such as that. disclosed in applicants previously mentioned copending. application, Serial No. 647,677, filed February 15, 1946.

Reverse drum drive -In order to drive the drum in reverse, it is necessary to manually engage clutch 33, thus lockingthe shaft 46 to the shaft 43-, and also supply air under pressure to the pipe 85, cylinder are and pipe II'I. Under these conditions, power 11 is supplied through the chain 38 and sprocket 39 to the internal shaft 49 to rotate the planet cage I02 of the transmission unit 65 in a counterclockwise direction, as viewed in Figure 4. The application of air under pressure to the cylinder 94b renders the one-way clutch blocks 94 operative to lock the flange 93 and, consequently, tubular shaft 95 against clockwise rotation, as viewed from the right-hand end of the transmission 4I. Thus, while the planet cage I02 rotates in a counterclockwise direction, the gear I99 is held stationary. This effects a reverse rotation of the shaft 44 with respect to the direction of rotation of the shaft 49 at a 1-1 ratio. Accordingly, two different reverse drum speeds may be secured, depending upon the condition of the two-speed planetary drum transmission I23. \Thus if, in the example given, the planetary transmission is in its 2-1 speed ratio, the overall speed ratio between the shaft I2 and the drum will be 6-1. This ratio is achieved when no air is supplied to the pipes I24 and I45. By supplying air under pressure to both of these pipes, a 1-1 drive connection through the planetary transmission I20 is provided, with the result that the overall speed ratio to the drum from shaft I2 will be 3-1.

Forward table drive When it is desired to drive the table forwardly, clutch 56 is engaged by supplying air under pressure thereto. The transmission is then capable of driving the table at four different speed ratios in the following manner. To establish the lowest speed ratio, which, in the example given, is a ratio of 24-1, between the shaft I2 and the table, air is supplied to clutch 31, pipe 85 and pipe I45. The drive to the table will then be from engine 2 to shaft 39 and thence by sprockets 36 and 43 to the tubular shaft 44. Since air is supplied to the pipe I45, the drum 48 is disconnected entirely from the sprocket 41, thus permitting a free rotation of the shaft 44. The cone clutches II6 of planetary transmission 85 will be engaged by the springs II9. This looks the shaft 49 to the shaft 44, thereby establishing a direct drive from the sprocket 43 to the shaft 49 from which the table is driven through change gears 59 and I, clutch 56, sprockets 55. 51 and 59 and the chain 6|.

In order to establish the second speed ratio, which will be 12-1 in the example given, the air supplied to clutch 31 and pipe 85 is cut off, leaving an air supply under pressure to the clutch 56 and pipe I45. Under these conditions, the drive to the table is from engine 3 to chain 38 and thence to the tubular shaft 49 and through the planetary transmission 64, which will then be in its 2-1 speed ratio. Since the planetary transmission unit 65 is still locked in a 1-1 ratio, the output shaft 66 of transmission unit 64 will be fixed with respect to and drive the shaft 49 and, consequently, will drive the rotary table which is connected thereto.

In order to establish the third speed ratio, the only change required from the conditions described above for the second speed ratio is to supply air under pressure through the pipe 9| to effect engagement of the planet clutches 81 of transmission unit 64. This looks the transmission unit 64 in its 1-1 ratio and thus provides an increased drive speed to the shaft 66 and thence through transmission unit 65 to the table drive shaft 49.

In order to establish the fourth or highest 12 speed ratio for the table, air is supplied only to the clutch 56 and pipes 9I, II'Iand I24. This maintains the 1-1 speed ratio through the planetary transmission unit 64 but effects a disengagement of the clutches I I 5 of transmission unit 65. At the same time, it looks shaft 44 stationary by reason of its connnection to the drum planetary transmission unit I29, which, by reason of the supply of air to the pipe I24 and the absence of an air supply to the pipe I45, is locked against rotation. With shaft 44 stationary, shaft 49 will be driven in the same direction as shaft 95 but at twice the speed, thereby establishing an overall speed ratio between shaft I2 and the rotary table of 3-1.

Reverse table drive To reverse the table drive, air under pressure is supplied to clutches 31 and 56, pipes 85, III and I45, and cylinders 94b. The supply of air under pressure through pipe I45 disconnects the drum 48 from the sprocket 41 and thus permits the delivery of power from shaft 30 through sprockets 36 and 43 to the shaft 44 without causing drum rotation. The supply of air under pressure to the cylinders 941; permits return of the one-way clutch blocks 94 to operative position, thus looking the flange 93 and shaft 95 against counterclockwise rotation, as viewed in Figure 4. With shaft 95 thus held stationary and shaft 44 rotated in a counterclockwise direction, the planet cage I92 and, consequently, the shaft 49 will be rotated in a direction opposite to that of shaft 44 but at the same speed. This provides a reverse table drive at a ratio of 24-1. During such reverse table drive, the supply of air to the pipe renders the clutch blocks I8 inoperative, thus permitting the planet cage I4 of transmission 64 to rotate freely in a counterclockwise direction under the influence of the counterclockwise rotation of shaft 40 While shaft 66 is held stationary.

Automatic drilling The transmission of the present invention may also be employed to control the pressure of the drill bit on the bottom of the hole during drilling operations and to vary that pressure inversely with respect to the table torque but at a lower percentage rate of change in order to provide an automatic weight control and at the same time prevent twist-offs of the drill stem due to excessive drill bit pressure.

During automatic drilling, engine I is connected to the slush pumps by engaging clutch I8; engine 2 is connected through its torque converter 8 directly to the drum through chains 25 and 28, shaft 39, sprockets 36, 43, 45 and 41 and the drum planetary transmission I20 by engaging clutch 31; and engine 3 is connected to the rotary table through sprockets 3I, 33, 34 and 38, transmission unit 4I, shaft 49, etc. Since during drilling operations the rate of rotation of the hoisting drum is negligible, the torque converter 8 associated with engine 2 will be operated under substantially full stall conditions. As a result, the torque which is transmitted from engine 2 through the torque converter 8 and the direct drive connections to the drum will deliver to the drum a substantially constant torque which may be adjusted at will by varying the throttle setting of the engine. This torque is preferably so adjusted in this manner or by changing the speed ratio of the drum planetary transmission I20 that it balances the major portion of the weight of the drill stem and other mechanism supported by the hoisting drums It will be observed that the l lro-v portion or the drill stem supporting" force which islthus supplied. by engine 2 and torque converter Q will remain. substantially constant, regardless of variations in the rate of drill bit: penetration.

During: automatic drilling, the power required to rotate the table, as previously mentioned, is supplied from engine 3 to the tubular shaft .470. and thence through the. transmission unit 64 to the input shaft. 9.5 of the planetary transmission unit: 65. Since the output shaft 44 of: the transmission 65 is fixed to the hoisting drum through sprocket 45, chain 46', etc, the; shaft 44 will remain substantially stationary. As a result,

the planetary cage I02 and shaft 49 will rotate in a counterclockwise direction, as viewed. in Figure 4, at a speed twice that of the shaft 95 and will in turn drive the rotary table in the manner previously described. However, the torque reaction imposed upon the output shaft ll of planetary transmission 65 by the table drive torque applied through shaft 95 will act on the Shaft 44 in a counterclockwise direction, and will be transmitted through the sprocket 45, chain 48, sprocket 4 1 and the planetary transmission [20 to the hoisting drum in a direction to assist in supporting the weight of the drill stem. This added increment of drill stem supporting torque will constitute. a fixed proportion of the table torque and, consequently, will, on an increase in the table torque, decrease the pressure of the drill bit, on the. bottom or the hole, and vice versa in the manner more fully set forth in. ap-

plicantis copending application, Serial No. 602,-

etary transmission unit I20, or by changing the relative sizes or the gears emplo ed in the mometary transmission unit 65. For a transmission having a design and construction of, the illustrative ratios mentioned, the drill stem supporting torque supplied to the hoisting drum as the result of a table torque reaction will be 2. 6 times the table torque, regardless of the spee ratiov provided by transmission unit 64.

Cat head and sand reel drive Since the cat heads are mounted on the shaft 52 and the sand reel is likewise driven from that shaft by sprockets 62, they may be o erated either at; four different speed ratios forward or in reverse in the manner described above in connection. wi h. t e forward table drive t will be appreciated, however, that in such case, the table drive clutch 56 w ll. be d sen a To facilitate an understanding of th manner in. which the different speed ratios and drilling functi s re p i rmed by he m chanism. of

the. present inv ntion r ference ay b had o the. following chart, which shows the various control nstrumentalities to which air under pressure must b suppl d o dj t t m chanism for each of its principal operating conditions.

The letter X in the chart indicates that the instrumentality indicated at the top of the column in whi h he X. appears i to r i operating air underp e s e, Under om ircum stances. a s pply of air to o or more of the clutches 1.8,, 23; and 35 is p ional, dep ndin upon the number of en ines r qu red to handle th oad, Where a choice in his r sp t s p siblc. the. letter appea s in the chart. indicating; that an air supply is optional.

Speed Ratios Control air supply chart Clutches Transmission Elements Forward Drum:

High'lVr n. Reverse Drum: (Engage, 63 Manually) .0 O 0 High, 3-1 O 0 Forward, Table:

Low, 24-1 0 0 2nd, 12-1 0 0 3rd, 0 0 High. 3-1.. ..v o. o. 0. Reverse Table, 24-1 0 X Automatic Drilling:

LcwDrumTov u fi Fast Table, 3-L.

OOOQ

appreciated that air must be supplied through pipe ll 'l' to efi'ect disengagement of the cone clutches 5 of the transmission unit 65. Two difierent table drive speeds may be secured, depending upon whether or not air under pressure is supplied to the pipe ill to control the speed ratio 01 the transmission unit 64 in the manner previously described.

It will be appreciated that the magnitude of the drill stem supporting torque supplied to the drum 48 by the torque reaction from the table drive mechanism may be varied as compared with the table torque by changing the ratios of thechange speed gears 56 and 5!, by changing the relative sizes or the sprockets G5. and Ill,

In addition to the. above, a still lower speed ratio of 2411 may be obtained for hoisting by driving the drum from shaft through sprockets 36, 43, i5 and 41 while the drum transmission I2!) is in its low ratio of 2-1. This is achieved by engaging clutch 31 and supplying air under pressure to line H! to disconnect the drive throu h transmission 1- T rum ill then be driven by engine a, or by additional engines if clutches or 23 or both are engaged.

Alternatively, the four speed ratios of 12==l, 6-1, 3-1 and l- /zl for the hoisting drum may all be obtained while the. drum transmission I20 s in its -1 ratio. Th s is accomp ed by dr ing the. drum iroin shaft 39 through prockets by. changing the speed ratio of the drum plans :5 38., 43, and 61', in the manner d s ribed above costly than conventional transmissions.

while air under pressure is supplied to lines I24 and I45 to obtain a 12-1 ratio. The 6-1 ratio is then obtained by driving through transmission 4| while the latter is in its low gear ratio (no air supplied to lines 85, 9I, II3 and Ill). The 3-1 ratio is then obtained by supplying air under pressure to line SI, and the 1 /2-1' ratio by supplying air under pressure to lines 9|, H3 and 1. Since for most purposes a geared ratio of 12-1 is sufiiciently low, particularly when torque converters are used between the engine and drum, it is thus possible to eliminate the transmission I altogether and utilize a conventional hoisting drum, if desired. This would eliminate the low speed reverse drum drive and the high drum torque automatic drilling drives given on the above table, but low speed reverse is seldom required on the drum and the torque to the drum during automatic drilling can be varied widely by changing the speed of engine 2.

In addition to the above, it may be noted that at any time the hoisting drum may be entirely disconnected from the transmission mechanism by supplying air under pressure to pipe I without supplying air to pipe I24, the drum may be locked in a stationary position by supplying air to pipe I24 but not to pipe I45.

While only one form of the invention has been shown and described, it will be apparent that variations in the design and details of construction may be indulged in without departing from the spirit of the invention or the scope of the appended claims. Thus, for example, any desired number and arrangement of engines may be employed, one or more engines may be connected through a single torque converter, as distinguished from an individual torque converter for each' engine, additional planetary transmissions similar to the transmission unit 64 may be employed in series with the transmission unit 64, either ahead of or behind the transmission unit- 65, and the drum transmission unit I20 may be omitted, if desired. The particular type of sprocket and chain connections and the speed ratios of those connections, as well as relative sizes of the gears, may likewise be varied to meet any desired operating requirements. Likewise, the type of multiple speed ratio transmission mechanisms employed may be planetary transmissions of a different type than that indicated generally at 64 or, with the exception of the transmission unit 65, need not be planetary transmissions. In addition, other forms of clutches and brakes may be substituted for the cone clutches 81, H5 and I23 and the one-way clutch blocks I8, 94 and I05 without changing the performance characteristics of the transmission.

An important features of the invention resides in the use of the low torque three-speed constant mesh geared transmission 4 I. The constant mesh geared type of transmission, in which friction clutches control the gear ratio, is highly desirable because of its compactness and ease of control. However, such transmissions are more In the present case, a substantial saving in cost and size is achieved by limiting the maximum torque on the-transmission to a relatively low Value and thus making possible the use of a smaller and less expensive unit. This result is achieved by a combination of several features: first, by compounding, i. e. connecting in series, two twospeedtransmissionunits 64 and 65, one of which gives an overdrive orstep-up speed ratio and the other a step-down speed ratio, the maximum load on the gear teeth is kept at a low level; sec ond, the major portion of the torque multiplication is placed between the transmission 4| and the hoisting drum; and, third, the fact that the transmission 4I provides only three speed ratios is taken care of by providing a fourth speed ratio change independently of the transmission, either in a special transmission positioned within the hoisting drum brake flange within the space occupied by a clutch on conventional hoisting drums or by an auxiliary chain drive'for low gear which by-passes the transmission.

Certain of the features herein claimed are dis closed in applicants copending applications, Serial No. 647,677, filed February 15, 1946, and Serial No. 602,619, filed June 30, 1945.

What is claimed is:

1. A transmission for selectively driving either one of two power consuming instrumentalities in reverse or forward at a plurality of speed ratios, comprising a planetary transmission consisting of three interconnected elements, one of said instrumentalities being connectable to one of the elements and the other to another of the elements, means for selectively delivering power directly to each of the elements independently of the other elements, selectively operable means for holding either one of two of the elements stationary, and means for fixing one of said elements against rotation relative to another.

2. A transmission for selectively driving either one of two power consuming instrumentalities in reverse or forward at a plurality of speed ratios, comprising a planetary transmission consisting of three interconnected elements, one of said instrumentalities being connectable to one of the elements and the other to another of the elements, means for selectively delivering power directly to each of the elements independently of the other elements, selectively operable means for holding any one of the elements stationary, and means for fixing one of said elements against rotation relative to another.

3. A transmission for selectively driving either one or both of two power consuming instrumentalities in reverse or forward at a plurality of speed ratios, comprising a planetary transmission consisting of three interconnected elements, one of said instrumentalities being connectable to one of the elements and the other to another 7 of the elements, means for selectively delivering power directly to each of the elements independently of the other elements, selectively operable means for holding either of two of the elements stationary, and means for fixing one of said elements against rotation relative to another.

4. A transmission for selectively driving either one or both of two power consuming instrumentalities in reverse or forward at a plurality of speed ratios, comprising a planetary transmission consisting of three interconnected elements, one of said instrumentalities being connectable to one of the elements andthe other to another of the elements, means for selectively delivering power directly to each of the elements independently of the other elements, selectively operable means forholding any one of the .elements stationary, and means for fixing one of said elements against rotation relative to another.

5. A transmission, including a pair of axially spaced concentric gear members, a planet gear support member journaled concentrically. with respect to said 1, gear, members, a planet gear fixing the support with respect to cluster journaled on said support member and having gears meshing respectively with said first mentioned gear members, a pair of power takeoffs adapted to be connected respectively to said support member and one of said first mentioned gear members, means for selectively delivering power directly to either of said first mentioned gear members or to said support member independently of the other members, selectively operable means for holding either said support member or one of said first mentioned gear members stationary, and selectively operable means to prevent relative rotation between said first mentioned gear members.

6. A transmission, including a pair of axially spaced concentric gear members, a planet gear support member journaled concentrically with respect to said gear members, a planet gear cluster journaled on said support member and having gears meshing respectively with said first mentioned gear members, a pair of power takeoffs adapted to be connected respectively .to said support member and one of said first mentioned gear members, means for selectively delivering power directly to either of said first mentioned gear members or to said support member independently of the other members, selectively operable means for holding either said support member or either one of said first mentioned gear members stationary, and selectively ope!"- able means to prevent relative rotation between said first mentioned gear members.

7. A transmission, including a pair of axially spaced concentric gears, a planet gear support journaled concentrically with respect to said gears, a planet gear cluster jcnrnaled on said support and having gears meshing respectively with said first mentioned gears, a pair of power take-offs adapted to be connected respectively to said support and one of said first mentioned gears, selectively operable means for delivering power to either of said first mentioned gears, selectively operable means for holding the support stationary, and selectively operable means for on of said first mentioned gears.

8. A transmission, including a pair of axially spaced concentric gears, a planet gear support journaled concentrically with respect to said gears, a planet gear cluster journaled on said support and having gears meshing respectively with said first mentioned gears, a pair of power take-offs adapted to be connected respectively to said support and one of said first mentioned gears, selectively operable means for delivering power to either of said first mentioned gears, selectively operable means for holding either the support or one of said first mentioned gears stationary, and selectively operable means for fixing the support with respect to one of said first mentioned gears.

9. A transmission including a pair of aligned shafts at ,least one of which is tubulangears on the adjacent ends of said shafts respectively, a planet gear support journaled coaxially with respect to said shafts, planet gears journaled on said support and meshing with said first mentioned gears, a shaft journaled within said tubular shaft and connected directly to said support, a source of power connected to one of said shafts, and a pair of power take-offs for the rotary table and hoisting drum adapted to .be connected to the other shafts respectively at points on opposite sides of said first, gears.

10. A hoisting drum having ,a brake vfiange fixed thereto. at one end, a combined planetary two-speed transmission and clutch mounted coaxially with respect to the drum and within said flange, said transmission including a pair of concentric gears connected by planet g ars, a support for the planet gears concentrically journaled with respect to said first gears, selectively operable means located within said flange for holding said support stationary, selectively operable means for fixing said concentric gears against relative rotation, and means for driving one of said concentric gears.

11. In a well drilling machine, a plurality of engines, a hoisting drum, a rotary table driving shaft, a change-speed transmission, independent selectively operable means for connecting said hoisting drum and said rotary table drive shaft to the transmission, a countershaft, a drive connection fromone of said engines to said countershaft, a driving connection including a clutch between said countershaft and said hoisting drum independent of the transmission, a pair of sprockets fixed together and journaled on said countershaft, a clutch for engaging said pair of sprockets to said countershaft, a drive from one of said pair of sprockets to said change-speed transmission, and a drive from another engine to the other of said pair of sprockets on said countershaft.

12. In a Well drilling machine, a plurality of engines, a hoisting drum, a rotary table drive shaft ,a change-speed transmission, independent selectively operable means to connect the transmission to the hoisting drum or the rotary table drive shaft, driving connections including selec-' tively operable clutch means for connecting one or more of said engines to said transmission, and driving connections for selectively connecting one or more of said engines to said hoisting drum independently of said transmission, said driving connections and means being operative to simultaneously connect one engine to the rotary table through the transmission and another engine to the hoisting drum independently of said transmission.

13. In a well drilling machine, a plurality of engines, a hoisting drum, a rotary table drive shaft, a change-speed transmission, selectively operable means to connect the transmission to the hoisting drumor' the rotary table drive shaft, driving connections including selectively operable clutch means for connecting one or more of said engines to said transmission, driving connections for selectively connecting one or more of said engines to said hoisting drum independently of said transmission, said driving connections and means being operative to simultaneously connect one engine to the rotary table through the transmission and another engine to the hoisting drum independently of said transmission, and means in said independent drive connection for transmitting a torque proportional to the difference between the engine speed and the drum speed.

14. An engine compounding drive, including, in combination, a shaft, a pair of sprockets freely journaled on said shaft and fixed together, a clutch for connecting'the sprockets to said shaft, means for connecting an engine to said shaft independently of said sprockets, means for connecting a second engine to one of said sprockets, a power take-off including a disengageable clutch connected to the other sprocket, and a second power'take-off including a disengageable clutch connected to the first engine.

15. In combination, a shaft, a pair of sprockets 19 freely journaled on said shaft and fixed together, a clutch for connecting the sprockets to said shaft, means for connecting an engine to said shaft independently of said sprockets, means for connecting a second engine to one side of said sprockets, a power take-off connected to said shaft independently of said sprockets, and a second power take-01f connected to the other of said pair of sprockets, at least one of said power takeofis comprising a power transmitting mechanism containing a clutch so that by operating said clutches both power take-offs may be independently connected to separate engines or the other power take-off may be connected alone to either one or both engines.

16. A power transmitting apparatus for well drilling machines, including a shaft member and a member journaled freely on said shaft member, a pair of power take-offs having driving connections to said members respectively and adapted for connection one to the hoisting drum and one to the rotary table, separate engines connected respectively to said members. a clutch adapted to fix said members together, and disengageable clutches in the driving connections to said power take-offs. I

17. A power transmitting apparatus for well drilling machines, including a shaft member and a member journaled freely on said shaft member, a pair of power take-offs having driving connections to said members respectively and adapted for connection one to the hoisting drum and one to the rotary table, separate engines connected respectively to said members, a clutch adapted to fix said members together, a third engine, a Power take-off for a slush pump having a driving connection with the third engine, means adapted to connect the third engine to one of said members, and disengageable clutches in the driving connections to said power take-offs.

18. A transmission for a rotary well-drilling machine comprising a power take off shaft for driving a rotary table, a hoisting drum driving shaft, a planetary transmission having a pair of concentric gear members and a planet cage member and planet gears journalled on said cage member and meshing with said concentric gear members, a jack shaft, a rotary driving element, a pair of independent power sources, a driving connection between one power source and said jack shaft, a driving connection between the other power source and said rotary driving element, a disengageable driving connection between said rotary. driving element and one of said members, a disengageable driving connection between said jack shaft and another of said members, a disengageable driving connection between said last mentioned member and said hoisting drum driving shaft, a disengageable driving connection between said power take off shaft and the third of said members independently of the other members, means including a clutch for establishing a driving connection between said element and said jack shaft, selectively operable brake means for holding said third one of said members stationary, and selectively operable means for fixing one of said members against rotation relative to the other.

19. A transmission for a rotary well-drilling machine comprising a power take off shaft for driving a rotary table, a hoisting drum driving shaft, a planetary transmission having a pair of concentric gear members and a planet cage member and planet gears journalled on said cage member and meshing with said concentric gear members, a jack shaft, a rotary driving element, a pair of independent power sources, a driving connection between one power source and said jack shaft, a driving connection between the other power source and said rotary driving element, a disengageable driving connection between said rotary driving element and one of said members, a disengageable driving connection between said jack shaft and another of said members, a disengageable driving connection between said last mentioned member and said hoisting drum driving shaft, a disengageable driving connection between said power take off shaft and the third of said members independent of the other members, means including a clutch for establishing a driving connection between said element and said jack shaft, selectively operable brake means for holding said third one of said members stationary, and selectively operable means for fixing one of said members against rotation relative to the other.

20. A transmission for a rotary well drilling machine, comprising a power take-off shaft for driving a rotary table, a hoisting drum drive shaft, a planetary transmission having a pair of concentric gear members and a planet cage member and planet gears journaled on said cage member and meshing with said concentric gear members, a disengageable driving connection between one of said members and the drum drive shaft, a disengageable driving connection between said power take-off shaft and a second of said members independent of the other members, two independent sources of power, a disengageable driving connection between one of said sources of power and the third of said members, a disengageable driving connection between the other power source and said drum drive shaft independent of said transmission, and selectively operable means for fixing two of said members against relative movement or holding said second one of said members stationary in order to provide two difierent drive ratios to said drum drive shaft from said one power source through said transmission or permitting independent movement of all three members to effect simultaneous torque transmission from said one power source to said drum drive shaft and said power take-off shaft through said transmission.

CHARLES M. OLEARY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 384,560 Bugbee et a1. June 12, 1888 594,195 Cooke Nov. 23, 1897 725,223 Crawford Apr. 14, 1903 813,461 Stacks Feb. 27, 1906 902,856 Cave Nov. 3, 1908 1,413,292 Rauscher Apr. 18, 1922 1,795,706 Black Mar. 10, 1931 1,800,513 Davidson Apr. 14, 1931 1,808,222 I-Iild June 2, 1931 1,947,862 Lucas Feb. 20, 1934 1,990,810 Young Feb. 12, 1935 2,282,597 Archer May 12, 1942 2,316,131 Cardwell Apr. 6, 1943 FOREIGN PATENTS Number Country Date 22,661 France Aug. 4, 1921 28,520 Great Britain Dec. 28, 1904 

